Heat-resisting iron



' To all whom it may essen.

T @FFHCE.

mnncn D. SOHENCK, or DAYTON, omo, AssIGNoR TO THE DURIRON COMPANY, me,

A CORPORATION or NEW YORK.

HEAT-RESISTING EON.

No Drawing.

concern: Be it known that I, PIERCE D. SoHENoK,

a citizen of the United States, and a resident of Dayton, in the county of Montgomery and State of Ohio, have made a new and useful Invention in Heat-Resisting Iron, of which the following is a specification.

The invention relates to an alloy wh ch is largely iron, and which will resist a high degree of heat, so that the compositlon may be loosely termed a heat reslsting 1I0Il. The invention isdesigned to take the place of the relatively expensive compositions now on the market and containing relatively hlgh proportions of the raremetals. The primary ingredients of the COIDpOSIUOII are iron, nickel and chromium, the latter bemg used in relatively small quantities, so that the composition may be used for many purposes where other compounds havingapproximately the same heat reslstlng qualit es cannot be used because of the prohibitlve cost. A further object of the invention is the production of a composition or alloy of the character above specified, which can be machined without difliculty, being like cast iron in such respect; which is not brittle, being in fact somewhat malleable; which is acid resisting to a high'degree, and which is relatively tough. r

In its best form the composition contains about 85 parts of iron, 5 to 15 parts of nickel and 1 to 3 parts of chromium. As a specific example, a very satisfactory composition comprises 10 parts of nickel, 2 parts. of chromium, and the balance iron.

In making the compound. an electric or open hearth furnace is preferably employed, the chromium being added in the from of ferro chromium and melted with the iron. The bath is then skimmed and the nickel added.

The iron employed is low in silicon, pref erably less than 1%, as any amount over 1% tends to injure the acid and heat resisting qualities of the composition. The iron is also preferably low in carbon, preferably 1 to 1%% or less. The composition thus produced is relatively cheap and 'will stand 2200 degrees F. without oxidization and 2600degrees F. without melting. Itis tough and somewhat malleable, can be easily cast-and Specification of Letters Patent.

combined with toughness of too Patented Nov. 29, 1921.

Application filed April 12, 1920. Serial No. 373,326.

machined, and has high acid resisting qualities. The field of use is therefore very wide.

It will be understood that the proportions specified may be varied somewhat without departing from the invention, and also that certain other ingredients of more or less neutral character may be added without greatly affecting the quality of the product. For instance, cast iron normally contains a small percentage of manganese as an impurity and some other impurities in minute quantities, which do not affect the composition appreciably. The invention comprehends the use, incidental or otherwise. of such ingredients. In fact I have found that even additional manganese may be added without injurin the composition to any extent, although prefer to omit such element because it involves no advantage and means additional expense. There are many other elements which can similarly replace a portion of the iron and are more or less neutral in their effect upon the iron and acid resisting qualities ofthe composition. The term iron therefore is not limited to pure 100% iron but comprehends iron with such expected impurities as do not unfit it for its intended use and iron containing small percentages of other metals which are more or less neutral in their effect upon the composition resulting. I

I have found that the proportions of nickel and chromium as heretofore specified give a product which best suits the requirements for which the iron is intended, viz. one which has great heat and acid resisting qualities, and of just the right degree of hardness to permit machining without brittleness. If more nickel is added, the composition is softened and made reat price for general use. If decreased lielow the amount specified, the composition becomes too hard and brittle and lacks the desired degree of toughness. Similarly, if the chromium is increased, the composition is hardened so that it is 'diflicult to machine, without increasing the heat and acid resisting qualities, and the cost increased. A lowering of the amount of What I claim is: 1. A heat resisting iron composition comprising approximately 10 per cent. nickel, 2 percent. chromium and the rest substan- 5 tially all iron.

2. A heat resisting iron composition comprising approximately 10 per cent. nickel,

2 per cent. chromium and the rest substantially all iron with any silicon content in the ironless than 1 per cent. 10 In testimony whereof, I have hereunto subscribed my name this 30th day of March,

PIERCE D. SCHENCK. 

